Add sig-etcd-leads to approvers

Signed-off-by: joshjms <joshjms1607@gmail.com>

Author: joshjms

registry.k8s.io/images/k8s-staging-etcd/OWNERS

@@ -4,8 +4,10 @@ options:
   no_parent_owners: true
 approvers:
   - release-engineering-approvers
+  - sig-etcd-leads
 reviewers:
   - release-engineering-reviewers
+  - sig-etcd-leads
   - jpbetz
   - wenjiaswe
   - jingyih